Insulin-like growth factor binding protein-3 in the detection of fetal Down syndrome pregnancies.
OBJECTIVE
To study the usefulness of maternal serum insulin-like growth factor binding protein-3, a potential cell growth inhibitor, in second trimester prenatal screening for fetal Down syndrome.


METHODS
Three hundred and forty-two samples from normal pregnancies and nine fetal Down syndrome pregnancies were analyzed for insulin-like growth factor binding protein-3 levels by radioimmunoassay. Data were converted to multiples of median (MoM) and analyzed statistically to compare the differences between control and Down syndrome pregnancies.


RESULTS
The mean insulin-like growth factor binding protein-3 MoM of Down syndrome-affected pregnancies (1.09) was significantly higher than that of the normal pregnancies (1.00) (P < .01). Insulin-like growth factor binding protein-3, in combination with maternal serum alpha-fetoprotein (MSAFP), hCG, and maternal age, detected 89% of Down syndrome pregnancies at a screen positive rate of 2.1%. This compares favorably to the standard combination of MSAFP, hCG, and unconjugated estriol (E3), which had a 66.7% Down syndrome detection rate and a 4.1% screen positive rate in our study samples.


CONCLUSIONS
This retrospective analysis suggested that the inclusion of insulin-like growth factor binding protein-3 into the triple screen program to replace unconjugated E3 might enhance the detection rate of fetal Down syndrome pregnancies. These data need to be confirmed by a larger prospective study.
Chu
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DC
Department of Obstetrics and Gynecology, University of Alabama at Birmingham, 35294, USA. obar020@uabdpo.dpo.uab.edu
Hsu
C
C
Wenstrom
K D
KD
Boots
L R
LR
D000328:Adult; D015415:Biomarkers / Q000097:blood*; D006063:Chorionic Gonadotropin / Q000097:blood; D004314:Down Syndrome / Q000175:diagnosis*; D004964:Estriol / Q000097:blood; D005260:Female; D005315:Fetal Diseases / Q000175:diagnosis; D006801:Humans; D007231:Infant, Newborn; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood*; D016015:Logistic Models; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011296:Prenatal Diagnosis; D011863:Radioimmunoassay; D012189:Retrospective Studies; D000509:alpha-Fetoproteins / Q000032:analysis
D015415:Biomarkers; D006063:Chorionic Gonadotropin; D018972:Insulin-Like Growth Factor Binding Protein 3; D000509:alpha-Fetoproteins; D004964:Estriol